Background The musculoskeletal symptoms, as well as extra-articular manifestations of ankylosing spondylitis (AS) decrease quality of life and productivity and result in significant direct and indirect costs, with the latter being even higher than the former. However, data on the economic burden of AS in Turkey are scarce.

Objectives To describe indirect resource utilization for AS patients attending at rheumatology outpatient clinics of tertiary health centers in Turkey over a 1-year period and to identify demographic factors and clinical assessment measures associated with indirect costs.

Methods Medical records of 650 prevalent AS patients attending rheumatology outpatient clinics in seven tertiary healthcare hospitals nationwide were examined to assess annual indirect healthcare costs. Eligible patients were age ≥18 and diagnosed with AS for at least 12 months. We assessed relevant indirect cost-related variables and activities, and actual costs. Multivariate regression was used to determine the effects of demographic factors and clinical assessment measures on indirect costs. The Pearson correlation matrix and the association between disease assessment measures and indirect costs were assessed.

Results Mean (±SD) patient age was 40.1± 11.33 years, with 35% of the patients being female. 55% were employees, of which 59% had employer permission to miss work due to AS, costing patients an average €412 annually due to workday loss as calculated based on income level. 2% of the patients had other AS-related consultations not covered by insurance (acupuncture, homeopathic, other), bringing their average annual burden to Є2,482. 10.46% of the AS patients incurred additional AS-related costs (e.g. need for new car, apartment, special equipment), spending an additional Є1,978 per year. 6.92% of the patients required caregivers, costing €546 annually. Multivariate regression showed that age and gender played no significant role related to the increase in indirect costs. Patients needing AS related equipments reported significantly higher Global Disease Activity (GDA), visual analog scale (VAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and lower EuroQoL health status (EQ-5D) scores

Conclusions AS represents a considerable economic burden to Turkish Society. Studies assessing chronic disease costs, especially in developing nations, are important to determine efficient allocation of the limited resources in such regions.

Acknowledgements This study was sponsored by Pfizer Turkey

Disclosure of Interest N. Akkoc: None Declared, H. Direskeneli: None Declared, H. Erdem: None Declared, A. Gul: None Declared, Y. Kabasakal: None Declared, S. Kiraz: None Declared, B. Durguner Employee of: Pfizer, O. Başer: None Declared, V. Hamuryudan: None Declared